PSV Change Over Schedule

[fasco]

Is there a Standard which provides clear guidance on the schedule or cycle of PSV change over from Primary to standby?

 

[cheute79]

I am aware of only the IIAR (ammonia industry) standard that provides clear guidance. As I recall, it requires annual or upon a relief incident, whichever comes first. I've never found any other code, rule or standard for any other industry or general use.

 

[stookeyfpe]

CGA/ANSI K61.1 also specifies a frequency for relief devices on bulk NH3 pressure vessels that are not part of a refrigeration system.